/Engine/Source/Runtime/Core/Public/Math/UnrealMathUtility.h
Same as CubicCRSplineInterp but with additional saftey checks. If the checks fail P1 is returned.
template<class U> static constexpr U CubicCRSplineInterpSafe ( const U & P0, const U & P1, const U & P2, const U & P3, const float T0, const float T1, const float T2, const float T3, const float T )